SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd3682844bb5ed9f27598c02546a12f4ae37f2102eceb464541bcd6f7921d70f' 
  AND token = 'yfiuMMadvoNjFkYK0h99lHPoehvK2GYrOErWOkmf+2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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