SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8e842bd9845c40569b37775ae260dd0cbbabfefa35dfd238cf39a178dab30d2' 
  AND token = 'CqYiXeSOxPFMfwqXaaxxyLcatXJtvuv7ZaUtdVellew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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