SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56e97e240648662064b241cb3533f68fff453aa4b2ea65534e38226af1ddc8fc' 
  AND token = 'y2dKV2MgaOAn6GJHSjQ5YdWKZy5zpJHwMh+TmiszFQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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