SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '31a70c9f7be6d68e79c198bdaf3efa671300782c52a353ae974c86bbdcb1cf28' 
  AND token = 'k8A9J4oGVdgAHztXi7BgKTVPQCFNGoqpa1xX3wSK/rY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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