SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50de7e1bdf920037e32eceb9b76b921f4c2a6c5fc1fd89fad51e79cdd467def2' 
  AND token = 'VzOoAUKtokXfxhAnFdJthrXDfBWv09JE5Yf32Ei3y3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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