SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f17154e6faa1c1f788b9caf16f3598b65e47d221374899232a689890e2f9e7a9' 
  AND token = '0eS3Yz4uzdWUCvo2hznm06YB8khJXYcxKI+UWC4DvKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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