SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '21fe46577a2d573d21e08c9b22fe9d64cfc04205975cea23e41d5a0dd94b11bb' 
  AND token = 'Z3HA8Ngiy/k8qciW/Zm22bfgvNy8kWmMPNLle1LJ6yM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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