SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f43bc4b531d30b9462dbf2fff617900391f02dfe3dac73113d7891d9100cb6b' 
  AND token = '+DeYpb+RJArSaeTAii90e2OeCtuDTw1/MaeTXS2bl5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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