SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0c27eed65a406640fa7802a7c65885618e357888f3256381fe23c5b84ba07cd' 
  AND token = 'crs71hf/y5RICmOxqAOplXEE4kMinXXr8kKFPifUnfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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