SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '60f9a20da8d5cea78058e83121ac679a936e6d91948ce150c1bfa23081e71283' 
  AND token = 'tzsVVfo9E/uxtbCRYYuRbdzIB7HxQ9AUhOYKjYZwVVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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