SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '60bb2e1cf3a9167bf2b5d081338bb0ebe406754ede61707b84618fed9e923d8b' 
  AND token = 'd4/2pj/6wQfYf9SBF+IK8X/xVCxpn4JFmkGUUl23W4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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