SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f8ebb52f9efc11c0c28c010ff84e223782d73424050a28e2d20b43c34f2ee83' 
  AND token = 'XG9rSSq6uXRDgAz/trGqcofjfJwmp+MuA7t9hIPtLzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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