SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52b07138e1c33b83f8e4f15619f7bcf74c9ca70ee9c3e43ba67a86fb9eec4923' 
  AND token = '54Fku3o2esDqHvmJZqq+7JjXZm+5RO9GSGWTq6BKk/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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