SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8644398e4f1b5d0c69569c954b41a11325f2952d525b0b30a59496bc2eb84a7f' 
  AND token = 'J/wq47ONinL5xdDaNWxzBT12ExrUwEG2USkClLsjoFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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