SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f118c95a6f9879ff606d7a42dd1d254aca6b097bb3871f5b30e825da4668a720' 
  AND token = 'HTSIl4TqMw7ihijuJu/z2YKYxjaJ58hv0gaQsbwsAUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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