SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9863df9dbbf188a9a08e14d30ddf3d61b90e47994e357ba2232faee2b142cf4f' 
  AND token = 'e8uSCinQHd/vBUxBj/w3TMlY7CdY+F5ekPnZuEWzg9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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