SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '400888a2ab2b74e511f3aaceaffb9a42e26dde22a344322ee1f5f577c5834f5c' 
  AND token = 'VoCMF9zXKp5EugI34YwY2+KpxlnWTNBhhn1Deh0clrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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