SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e7512b792151ff175ca855c5150497b5163ec9074ab9e269ced9c833cec691f' 
  AND token = 'LmpJCeFHKGGg0QMejwFhyRfCAGA9mEbWVEukCPryNsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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