SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb83291302ee85fc3e2011666ae348904ea0e1655b6457f623fb0f13ec527f35' 
  AND token = 'B29WRcTbhc47DJi37/NfYeHSnHoKPw0KmGiAgHQJ5n8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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