SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5b717f6817b4e246eb2b79500dbc7f9a2299fc3daf348d583c693f729bdd7d04' 
  AND token = '8kqLYDwHDVIaITSWHvtZT0ZCmUYAXUSbPXWKDbP0+Ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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