SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38d0eb9512ee78e679c51e9e69176593b9402aec266cba0164cf3425c8bd8c92' 
  AND token = 'j6hoXgGGPNBD1yMp4CRVlAvnzBC8q+t9B1JU9nabJmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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