SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f590972b6930c95aba79ce7e17c50cafdec272ce02d630ac186f89264349e942' 
  AND token = 'JfhxFDIrIBQuiFc04GaRpnSUkD8LhuYxsaL0K5mi+LI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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