SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '927588d929253f00011fe5a582c9fbe8f8096f18fb794a12e0949995269ad070' 
  AND token = '5JpSCKxMU1l9B0AE5THyWXEPD5fT7Dcc+/6bb2lHHmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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