SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dd56ea598cae73e3ebf3b6b40adab3e79a51ce818a038d192da00552d0909169' 
  AND token = 'Q8qcqFKVJNaeLgw41Uh5UGt811wqtF+JlREw/3wlW7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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