SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03b6b783d46dc695064c42cd11b5334ff3ddf76d2952c8ba8dc7cc5ceb750e90' 
  AND token = 'tuJ7wlv3A0wjE9oYb0YWTbEeVeHWY/nAIysqdw0MY5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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