SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6dfca0daeb79b9a0d588d5d840e56738af9bd16d7e2a0027be32fd548c924077' 
  AND token = '2Dj7MtAthzjvy6MOU8i/YR9EeciZJqoNOS9cDjIVup8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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