SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '476289b152a4e5f0b7a27cdf7c544949c92bc751323ae263577b079ecb812174' 
  AND token = 'vlafH0mRLN3shtGeYOmcWxvRSp+loe7L+7ceet9YOS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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