SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5384db423ee367acefa092426b31b2786112c03a9a85d60730d305b4c662175d' 
  AND token = 'uGsYIYSLXljjwc/ghM7cgcjM/47CjJcL935TJqu28yg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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