SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16597f8bbea5ce861d56cee4394b7741eb2c02195b28237bf0a3f9b0e15f4fda' 
  AND token = 'Ppcjtnf+KDcHAkgZ0QSeVOcCxAlVh0TvMtU7jOJG3Wc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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