SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06e92dbcd54d85c3c13df3317790608e2b5d43e0febcde6a71982da475c78de7' 
  AND token = 'vqKU8sfSL4tKzr4E/+ptPG7VyS51uiviQbWGOAmljJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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