SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1964635020ebf2a9d2005f8fd9afb9d66789f59390a458ab76b0c3fd6bef7e71' 
  AND token = 'nV+AVwgGgv1HQbC9EBAwdiAkATe/joGkko1PToJnE/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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