SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83310e5151e14159fc416dbf072b83174c73372334061df28e48fc4bafcd02bb' 
  AND token = 'xaTugybQQl3tAXA71wWDfC2lpkQEBJ8VhJRYOpuCdVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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