SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3557e5be266782a1666915ae732064b142fc69470e7103f2f313cfc37baef914' 
  AND token = 'hnbi0L9bljRhFFimyZDTrjZV5i5UWrZk+6bh65JcYJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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