SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71aba985a1eae96d94142b4842955459f0764cd012726d55458c70ce60a34695' 
  AND token = 'wW5C+VjY6NaEy0Ku75S/45FoVFX+Sxi/k0v0nxBjOYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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