SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd816521a5e4f5e93adb0def4050cbdde4fb5054282dd558ae460f866feb3e960' 
  AND token = 'Ap8wMK/AacLcOTCxnnvHXJjW0pHK2YY/C3HlQQqOuJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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