SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a828da45ffc3ac46a6d545b3195977346d28b4d6721e4059ffb4098e407a5f1' 
  AND token = '9crNycv6Q4ZEKVK+g/2THy54bYIETSYiP1IuVshTUGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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