SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff82c61ab050455b85646b74db488dec3d7c6430ed8db149f602a12936e6390e' 
  AND token = '45F3mhz/P0RpjgINbV4TigBrOBlMP4iN6Yhp2iKxe2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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