SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7a97a1b58f75ba613640baa829dfb450eddffa98f85acdbc6f9eafacdae8ba5' 
  AND token = 'aQVEtVIoHiUh4hyldhTGBiPr3pm3PYNCu7jqs7Gu20M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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