SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b554e9e9f9be278a109803a48df2b858a95cce7c95e1ef7c1416de00f50d14ac' 
  AND token = 'wrAlEmji7VPT8wHsticrsP8LqtmqsE0WGEeztXoMVz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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