SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ff041cc18796fcdc539b575066db56d79e12279e80bc920b8a50c7fa0c0ecc12' 
  AND token = 'BxkAYVcAYiuQoKZvIpYJZvMFadQ8DsuB35v+/l71xtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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