SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7eaeb1ef11aa7ae7617f63dd591120744d0d1f2d55198132467de713f3b6b215' 
  AND token = 'dLIstIS94RPYM1JboNYOnAp3ZQLJ9bWjCWFUp18BTyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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