SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '563b1b2368785eba31d9d05a85e16f0d35903728b9bc34607752f1564ed8c7d2' 
  AND token = 'rlZPlRW7Ks+ROmtw1Fh8Gzm8JXqXasJaK4fmEE9zWGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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