SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de3673a6b2a638491324668c03120ab4e3e7a260c545a12dda1a37b06a6865f4' 
  AND token = 'gupawBmBOgjjWnq7ik/0wTdIGRarHTcCQt5jYGG34UI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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