SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db57fcfd07727e6529720573118d1b6a55d2a0582edf8bea30492506556fb89e' 
  AND token = 'FQyLaFcKnK0npiQfLxZbKuxgKho0WpAfYGVhf4SOps8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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