SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ed3bc48dc18b7beafad7dbf62de97506723a09de9f0d5db8ce337043f89622b' 
  AND token = '6e/xYWneh97jGmBc1TNOXn8OmK+qJYw/qPLVGRus9Lc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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