SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bd9e3addda742b502fbb988246d54800c9609de6caad5334a0fc94ffc39012ff' 
  AND token = 'nEZb3GCVWzK+Ycevz3unIcRBaYh7IjU7X67DepN0qE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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