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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1bcdf232ba8128bf45a4a0e67dc6715e522a8f6915f1ef98cef6ce9457d0721' 
  AND token = 'VqQBWBsvWmC2iuruEjtELSqaKWkWoVRRRKDM7dL7aao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}