SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab52092ec18c9fd22e0bcbf9154cea6fa760616259227bdb4407072985177435' 
  AND token = '++FmqCAFxQACiBpBdl/iO+rdN0KFkhBfQ+caQqcFqws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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