SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1fce660e3688808b58fd85ed876a40d1fd183ae9961ab8905be0e7e96c58ccf' 
  AND token = 'VUb4T/eQgZStVnYGOTW/sSur5fIzy+FWm6vlySvEgl8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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