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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '651a717614bcbc57cb5a71aec8e13cf4ebc7cfa4e8ae40a765e8f5a3081e7258' 
  AND token = 'kHdMu2PCDFqqxMKVfiGacn10/VfgcxZ/ryuHce/QoFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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