SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '964f0fc7a967c68d744b1f5ba141178a84b81f0cb78cd9bf563805e2d14ac320' 
  AND token = 'FKQnDjJnBaxmCN8we6I+SSKK6ibDizmP6Y4BgVBciOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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