SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cb80556ee3ce7bb8a05c5826bf1fd7c5e83047b4b5d48ec9ce1b13817be277e' 
  AND token = 'JAx/tRtRRUzYID0/m/lqWDxIFdcBaslBlCv45OEmm8A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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