SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7318e075ee256b9a386043497503b06e1e2ac4eceaad88d56becb7a6f5310b02' 
  AND token = 'aq0QkrWlSxYgLvwUo1FJj4L/VUkIKaNFU5/ii43+jMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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