SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bb455809c1ed14eb16a8209cbcaf35d41f64d18516d3d991bc5c1bccea5dc80' 
  AND token = 'q+fddxFfv+IUup6hUJLnIQ/Yn3pdhBd3Fts9lKYap3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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