SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90fbc22a047ebd0e513eaca3ee53226cb476d4f15ebd8cb1ca24c5fccdc8af15' 
  AND token = '8deG0XVQ1jwMyCoiJJF5C+g1/GLc4jo51xjOuQd7v0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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