SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a128663a2df044f16909cb723c4f74301dfdd031900e71dc32ac75136b335630' 
  AND token = 'gukQotUK8k+qARyEfaTxmBBxNdgoIbV4YnffWCmPNpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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