SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3476b479fccfd03e95c298e62741e3af683965b2951435a62bfd1bbfa83f16f' 
  AND token = 'LMGqwF5tYiYWGI+orP/XSlfuQRTQmalTSO82H+vEtF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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