SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df75c97b0535d9decedc005abc421af2b7cb4a9084048312d1ebf0bcbf76c03e' 
  AND token = 'y5cURaYutNKS/U3EFhWA3FFi//cfO1aCLV7Rrc6wjZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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