SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96f3526ef44fca660144ee91a4c8bdbfa95e7fc9661cefb871162d0be50072eb' 
  AND token = '+bhwsrNFUMiT9TGmBG8qIqLNg/ZoWgdRR8iFXXroBg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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