SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37c3c9870970fe5c53c13f9bf238dbd983608eeff365857b6f2c12fd2ea3a0f1' 
  AND token = 'kCQPPYucuixIzx6U3Jw3zgtb4edpO9goKHP2ynmra0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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