SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '767da49fe0555886b2dd2d7ec9c9aa3c0f5350e3640cf55512bbb5bea917b9ef' 
  AND token = '08xZGISdDYbbF4QaRnH/mIeLyhcOnaynqTtDN/0DAvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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