SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd992cdbaf2649ba002d0b5473790ce958c80c9bcc1c17e569bd9ebc6e4571878' 
  AND token = 'po62Nvz1o2lXXoMPfYD5qqqPprGq48lM0/GjLKCv7HU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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