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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '795268e82482e2c29e8b08cd63e37e42d776d4f1547596c1c7ca9973bc57ce23' 
  AND token = '/0dFp5l0j9rqKJMBuP0Bu61XN+CO1rTOPYr2a9qoWs8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}