SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1a93d1d3b127d2364998fda936572400dbf3da1b01a474bf30cd5921ca44cee' 
  AND token = 'qnNJITnVR7gIsJgOo68UIpSYr9OJeaXIhjcITfRoKQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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