SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df18d543cce050fa854bd65be252f2ad18fc6fd713cae4a9a86c974ff7193ab8' 
  AND token = 'zmjuN0p6A4rwpsVG9/U1Oi+nbbki5ogQqnw2mGyq9oU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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