SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7543e78461036742c6f9759050f7ebbe5d9802f2f8b4ab78f63179de2e44abd' 
  AND token = 'PdCbFCmjwhmxVKJ/W3eDPI/jWyoZlUxhUHMjF600d8M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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