SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41cbff7b7945629486af3115ab1dcc1e888da09d0fb1e87841301a0264931663' 
  AND token = 'WJeL8ZQYSrzQxUFiaiu0jpOILipwpfqlEXXIVwbkY5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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