SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '830e24972cf49e8efdb496630ec3227561f35ca878824deda0992eb11fcb6c03' 
  AND token = 'D+1MSEMZOKNsQsyq8WXKXK4TOiWxlQF+vMZTfYEM3jQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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