SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dc24334b56fe0a48171c27abd20bcdc34fad2ccdbfb136259cef14932194500' 
  AND token = '2Rh1g66N91TvyWNBbSUW8ooFKZjm99QAmrkxt4PiZn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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